Automatic calendar



Feb. 7, 1939. z. JISKRA AUTMATIC CALENDAR Filed July 14, 1936 2Sheets-Sheet l Feb. 7, 1939. f

Z. JSKRA.

AUTOMATIC CALENDAR Filed July 14', 193e 2 Sheets-Sheet 2 s K oRNEYs.

Patented Feb. 7, 1939 PATENT GFFICE AUTOMATIC CALENDAR Zdenk Jiskra,Prague-Strasnice, Czechoslovakia Application July 14, 1936, Serial No.90,509

In Czechoslovakia March 30, 1936 13 Claims.

My invention relates to calendars and more particularly to an automaticcalendar which indicates the full date and can be actuated by a singlelever.

It is an object of my invention to provide for a device of the kindaforesaid which at any time displays the number and name of the day, thename of the month and the last figure of the year, and which, ifconnected with a clockwork,

l0 may also indicate the hour. On its back the calendar may furthermorealternately display the indications Forenoon and Afternoon.

It is another object of my invention to provide for a calendar of thiskind which renders automatically visible indications corresponding tothe different lengths of the months and of the leap years.

In a preferred modification particularly suited for the presentlyprevailing calendar-system, the

new calendar comprises five main discs which are provided withindications of parts of the' date and with openings for similarindications appearing on the other discs and which are formed on theircircumferences with indentations and teeth. These teeth cooperate with ahandor clockwork-operated lever in such manner that by a single movementof this lever performed at midnight all or part of the `discs arerotated to now display the next following date in the openlng of thefront plate behind which the discs are arranged. The discs with their'inscriptions, openings and teeth may be shaped in such a manner thatevery second movement of the lever, to be effected at noon, does notchange the date,

but only the Forenoon and Afternoon indication, while the movement thenfollowing changes the date, so that always the proper date appears onthe calendar.

It is apparent that for any other commonly accepted calendar system thisapparatus may be modified without exceeding the scope of the invention.

In the drawings affixed to this specification and forming part thereofone embodiment of my invention vin accordance with the presentprevailing calendar system is shown diagrammatically by way of example.

In the drawings A Figs. 1-5 are front views of the discs I, II, III,

IV and V, respectively.

Fig. 6 is a front view of an intermediate ring plate VI which may bearranged between each pair of adjoining discs.

Fig. 7 is a front view of the front plate O, the

one quadrant thereof being omitted to show clearly on a correspondingnumber of the sectors the relative positions of the discs I-V to thering plates VI.

Fig. 8 is a front view of an automatic calendar embodying this inventiondriven by a clock work. I

Fig. 9 is a side elevation, partly in section. Fig. 10 is a rear view ofa calendar after the clockwork has been removed therefrom.

Figs. 11 and 12 show in a front elevation and a plan View, respectively,on a larger scale, a 10 spring catch for engaging the teeth of thediscs.

Fig. 13 is a perspective View of the casing, showing the mounting of theintermediate ring plates. Referring to the drawings, O1 is the backcover of the calendar which is formed with a circum- Il ferential recessor opening M and an oblong, horizontally arranged opening P4 fordisplaying the indications Forenoon and Afternoon, O is the front plateformed with three openings: the oblong, horizontally arranged opening P1for the 20 number of the day and the name of the month;

`the similarly arranged opening. P3 for the name of the day, and thesmaller opening P2 for the unit of the years. Q is aclock-work mountedon the back cover O1. 25

Between the front plate and the back are' concentrically arranged thefive main discs, in the following sequence: I, II, III, IV, V. The fivediscs are loosely mounted on the hollow journal U traversing the centresof the front plate O and 30 the cover O1. Between the discs are arrangedintermediate ring plates VI shaped as flat circular rings (Fig. 6) whichdo not rotate about the journal U, but merely separate the discs fromeach other and from the front plate and cover 35 plate. The annularintermediate ring plates VI are secured against rotary displacement byprojections N1 abutting against the edges of the recess M of the coverO1 and are formed with` recesses M in which the catch Z may slide. These40 recesses are formed with an exact profile, while the prole of therecess M of the cover O1 may differ therefrom to a' certain extent (Fig.l0). More particularly the manner in which the intermediate ring platesVI are mounted between the 45 discs I and V is shown in Fig. 9. Anopening is cut out in the lower face of the cylindrical part of the backO1, as shown in Fig. 13, having the edge M cut out to clear the notchedportions M1 of the intermediate ring plates. 50

The intermediate annular plates VI are not fixed in the casing, but onlytightly inserted as shown in the upper part of Fig. 9. Those parts ofthese annular plates, in which the recesses are arranged, project beyondthe lower part of the 55 .casing, so that the annular plates aresecuredr against turning. The ring plates do not require any securingmeans to prevent axial movement.

When the parts are assembled, a ring plate y VI is first insertedagainst the inner side of the back of thecasing, as shown in Fig. 9(with the front plate O removed) then disc V is assembled on the bearingcollar U, thereafter another ring plate VI is inserted in the casing,then disc IV and so on to complete the assemblage.) While the ringplates VI are inserted in the casing so as to be immovable, the discs Ito V are freely rotatable therein.

, Thus all intermediate ring plates VI inserted in the casing aresecured against turning by the projections N1, engaging thecircumferentially spaced edgesin the bottom opening of the casing. Thelugs N1 are not bent but project only a slight distance beyond theperipheries of the ring plates VI. The discs carry marks orinscriptions, signs, words or abbreviations and/or gures and, besides,openings Lr-L4, through which, the inscriptions of the lower discs canbe read. The inscriptions and openings are arranged in such manner thatin every correct position the openings and inscriptions of the singlediscs behind the three openings of the front plate form a full date. Ontheir circumferences all discs are pron vided with teeth of unequalheight, the depths of the notches between the teeth being unequal also.The heights of the teeth and depths of the notches between the teeth aredened by nine concentrical circles A, B, C, D, E, F, G, H, J.

To each self-contained inscription of a disc is, allotted one tooth ofthe same disc.

Disc I as shown Ain Fig. 1 is circumferentially divided into fourteenparts, two for each day. It carries the names of theseven days of theweek and seven openings L1 enabling one to read the numbers of the days,the names of the months and the units of the years marked on the otherdiscs. On itsv circumference it is formed with seven teeth 1-7.

Disc II as shown in Fig. 2 is circumferentially divided into twenty-liveparts, two for each month, but three for the month March. It car--` riestwice the name of each month and three times the name March. Near thefirst name of each month (except March) the disc is solidv and carriesthe inscription f1.; near the second name (except March) the disc isformed with an opening L3 allowing the number of the day to appear intheopening P1 of the front plate. The opening L3 belonging to March isnext to the third occurrence of the name of this month, whereas next tothe second occurrence the inscription 2. is found. The disc is furtherformed with twenty-five openings Lz, one next to each of the names ofthe months, allowing the units of the years to be lread. through theopening P2 of the uresA 1-31 and is formed with thirty-one openings L4for the units of the years. On its circumference it carries thirty-oneteeth l-31, details of which will be described further below.

Disc IV as shown in Fig. 4 is circumferentially divided into twenty-veparts. It carries the following sequence of figures: 1, 2, 3, 3, 4, 5,6, 7, 7, 8, 9, 0, 1, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9, O, incorrespondence to the units of the years, wherein each figure whichfollows that of a leap year, is

doubled. The disc carries on its circumference tWenty-ve teeth 1-25 thedetails of which will be described further below. It need not be formedwith an opening.

Disc V as shown in Fig. 5 is circumfcrentially divided into eight parts.On its back side, which is directed towards the cover Oi, it carriesfourV times in alternation theinscriptions Forenoon and Afternoon. Onits circumference it carries eight teeth, the details of which will bedescribed further below. No opening need be provided therein.

'Ihe outline or profile of the teeth and notches is dened by the pointsof intersection of the circles A, B, C, D, E, F, G, H, J with the radiallines or rays 1, 2, 3, etc., the number ofv which on each disccorresponds with that of the circumferential teeth. On the back of thecalendar, i; e. on the outer side of the cover O1, is loosely arrangedon the pin R the flat lever Y which is provided with the flat springpawl Z shown in Fig. l1. The end of lever Y is bent at in such mannerthat it is perpendicular to the plane of the discs; the end engages therecesses M1 of the annular ring plates VI located between the discs.

The device operates in the following manner:

The teeth and notches `of the concentric discs partly overlap eachother. During a clockwise movement of the lever Y the pawl Z onlycatches the highest teeth of each combination of the discs, thusrotating only the discs belonging to those teeth, while the other discsremain at rest. The pawl Z carries the teeth along only until it reachesthe edge lc-l ofthe recess M1 where it stops, so that the active edge ofone tooth of each disc when at rest, coincides with said edge l-Z.

The recess Mr is'formed in the intermediate ring plates VI or in one ofthem with great exactness, while in the other intermediate ring platesVI as well as in the back it has only an approximate, but at anyrate'not narrowed form, as -follows: y

All the teeth while being formed on one side with an active edge forcoaction with the pawl Z,

are formed on the other side with a slanting edge ylor the cover O1,respectively. The circular length of the recess is somewhat more than1/7 of the circle B in order that with every second movement in theoperating direction the pawl Z can grasp a tooth of the disc I. Theinner edge ofthe narrow part of the recess M is delimited from point fto point g by the circle B. Point g is the point of intersection of thiscircle B with that radius which is separated from the edge lc-l by 55 ofthe circumference of the circle B. The

inner delimitation of the recess then runs from 75 point g to point hwhich is the point of intersection of the circle D with the radiusseparated from the edge Ic-l by $431 of the circumference of y thecorresponding concentric circle. The delimitation leads further frompoint h to point J' which is the point of intersection of the circle Jwith the radius separated from the edge lc-l by $55 of the circumferenceof the corresponding concentric circle. The edge of the recess thenfollows the circle J to the radial edge lc-l.

As to the movements of the lever Y, oscillations changing the date andbeing intended to be carried through at midnight alternate withoscilalations which only change the indication Forenoon into Afternoonand are intended to be carried through at noon; for disc V is shaped sothat on its circumference deep and shallow notches alternate. In a deepnotch the pawl Z is enabled to engage teeth of the other discs, thuschanging the full date, whereas in a shallow notch the pawl remains inits raised position and does not effect any change.

The adjusting and changing of the single indications proceed in thefollowing,A manner, provided that one of the deep notches of disc V isin the operative position:

(1) Normal changes of the calendar dae` in the course of a `month Thesenormal changes are brought about for all days between the fourth and thetwenty-eighth of every month. In this case only the teeth on the discIII which are delimited by the circles D and E, (from tooth No. 28 totooth No. 4) come in engagement with pawl Z. When the pawl Z proceedsfrom f to the edge k-Z, it rst slides on the edge f-g, being resilientlypressed onto this edge, and first catches the teeth ofthe discs I and V.It is not yet capable of catching' the teeth of the other discs, sincethey are"ra`dially lower than the solid part, delimited by f-g, coveringthese lower teeth. Beyond the point g the pawl Z passes onto the outeredge of the tooth of disc II, which outer edge lies in the circle B.Pawl Z cannot catch this tooth since the active edge of this tooth isseparated from the edge k-l by two teeth of disc II, i. e. by $125 oflythe circumference, so that the upper active corner of the tooth extendsbeyond g. Pawl Z therefore glides on the outer edge of the tooth of discII and slips off its slanting edge, being pressed by its ownelasticityonto the circumference of disc III. During further movement of the pawl,it meets the tooth of disc III, catches it and carries the teeth of thediscs I and III beyond the edge lc-I, so that the active edges of theseteeth coincide with the edge Ic-l. Since to the tooth of disc Icorresponds the name and to the tooth of disc III the number of the day,the date within the month has thus been changed. The name of the monthhas not been changed, since the tooth of disc II has not been moved.

(2) changs of the months After the 28th, 29th, 30th or 31st day,respectively, the month is changed and in the perforation of the frontplate O appears the name of the following month land at the end of ayear also the number of the following year. For every year there must beeffected twelve changes of this kind; they may be divided into fourgroups in accordance with the length of the months.

(a) Operation of the calendar at the end of a month with 31 days, forinstance January:

On the 28th of January the tooth No. 29 of the disc III, which toothcorresponds to the 29th day, is prepared for the following engagement bythe pawl Z. The tooth No. V30, however, is higher than No. 29 andtherefore overtops the edge g--h, so that with the following movement oflever Y the pawl Z would catch this tooth No. 30 and carry along twoteeth of the disc III. However, this does not happen, because the toothIII, 30 is covered by the tooth No. 3 of disc II which remains at restup to the 31st day. Beyond the tooth DI, 29 however the tooth II, 2,being otherwise free for engagement, is not caught by the pawl Z,because the notch following the tooth III, 29 is not deep enough.

On January 29th the tooth III, 30 is prepared for engagement. Thefollowing tooth, which is still higher, l. e. tooth III, 31, is coveredby the I tooth II, 3.

On January 30th the tooth III, 31 comes into position to be engaged bypawl Z upon the next movement thereof at midnight at the end of thisday. "I'he tooth III, Iis still covered by the tooth On January 31st thetooth III, 1 is engaged, which corresponds to February 1st, tooth III, 2being stillcovered by the tooth II, 3. As'the notch in disc III beyondthe tooth III, 1 extends down to the circle J, the pawl Z descends untilitA meets the tooth II, 2, which is now uncovered. 'Ihe pawl Z nowcarries along the discs IIand III, and the'. date changes to the firstof February. Now being located directly behind the tooth III, 2 the talltooth II, 3 is prepared for engagement. When changing over to the secondof February, this tooth is carried along so that in' the opening'of thefront plate appears the second inscription February, and the opening L3next to it of disc II; this second inscription February remains visibleup to the end of February, because the following tooth II, 4 has come inthe `position of engagement, which tooth is lower than the deepest pointof the notch between the following teeth of the disc III. The teeth ofthe disc III, which correspond to the third and the later days ofFebruary, are low, so that the pawl Z is only capable of catching onetooth at each oscillation, although in the month of February no talltooth is in position on the disc II between II, 3 and II, 8 which wouldexceed and thus cover the edge g-h during themonth of January.

(b) Operation of the calendar'at the end of a month with 28 days; forinstance February of a normal year.

On February 28th, the tooth III, 29 is ready for engagement, but thefollowing tooth III, 30 is higher and overtops the edge g-h, so that thepawl Z, while moving further grasps this tooth and causes the disc IIIto rotate to the extent of two teeth, since disc II is only formed withl1 tall teeth like II, 3 which work as described in the last paragraph,whereas tooth II, 5 is too low for such action. Consequently the 30th ofFebruary would now'appear in the opening of the front plate. Since,however, the notch between the teeth III, 30 and III, 31 extends down tothe circle F, while tooth II, 4 extends up to the circle E, the pawl Z,after having slipped into the notch between the teeth III, 30 and III,3l, will grasp also the tooth II, 4 and rotate the disc II to the extentof one tooth; there' now appears in the opening of the front plate thefull inscription A Z, since tooth II, 6, like II, 5, is too low to coverit, the disc III being again rotated to the extent of two teeth, wherebythe number of the rst day is carried behind the opening of plate O.Simultaneously the tooth II, 5 is carried along, so that in the openingappears the date 2. March, while the disc III is covered thereby.

On March 2nd the tooth IH, 3 is brought into position, which tooth,although not being higher than the edge g-h, is drawn a little beyondthe corner h, because the tooth III, 1 by means of which the disc hadbeen adjusted fory the preceding date, is formed at the top with a stepagainst which the pawl Z abuts, so that the disc',

III has been pushed forward by a little more than J/l of thecircumference and the tooth III, 3 has been drawn alittle beyondthecorner h. The pawl Z had made contact with the step of the tooth III, 1because it was prevented from slipping below it by the too shallow notchbetween the teeth II, 5 and II, l6. Now the pawl Z, while movingfurther, catches the teeth III, 3 and II, 6, whereby the number 3 of theday of the disc III and the word March and the opening for the numbersof lthe days of the disc II appear in the opening of the front plate.During these changes also the discs I and V have revolved.

The changes of the date which now follow are similar to those describedabove under (1) (c) Changes at the end of the month of February with 29days, viz. in a leap year.

In this case the influence of the third disc, i. e. the disc IV for theunits of the years,comes into action. In consequence of the arrangementof the gures on disc IV, described above, after each twenty yearsperiod, i. e. after one full rotation of the disc IV, the sameconditions prevail again. Therefore the operation of the disc IV inaccordance with the rules of the calendar is not limited in time. Thedisc IV will only fail in the case,- where a number of a century is notdivisible by 400 (as for instance the number 1900) so that this year, inspite ofits being divisible by 4, is not a leap year. In this case thedate on the calendar must be manually adjusted from February 28ththrough February 29th to March 1st.

The disc IV is formed with ve sets of teeth, each set consisting of fourshort teeth and one long tooth. Three of the short teeth of each setcorrespond to the three ordinary years whereas the'other short tooth andthe long tooth of each set correspond to leap year. The long teeth are lsomewhat similar to those of the disc II; they are however lower by onecircle, extending only to the circle C, and lacking the laterallyprojecting points or corners described above.

The change takes place in the following manner: On February 28th thetooth III, 29 is 'ready for engagement. The 'following tooth III, 30,which overtops the edge r1-h, is covered by a higher tooth of the discIV, so that the pawl Z only grasps the tooth III, 29 and brings February29th into position. Now the tooth III, 31 overtops the tooth of the discIV; in the following change of date the pawl Z therefore grasps thetooth III, 31, thus rotating the disc III again to the' extent of twoteeth ,and causing the number of f the 31st day to appear.Y The notchbetween the teeth III, 31 and I II, l is so deep that pawl Z carriesalong also the tooth II, 4, whereby the date 1. March, all on disc II,is brought into view and covers the inscription of the disc III in theopening of the front plate. Now the tooth of disc IV is overtopped bythe tooth III, 2, which is carried along together with the tooth II, 5in the following change of date. On disc III now appears the number 2,on disc II the date "2. March. y

In the following change of date only the tooth III, 3 is grasped, forthe tooth III, 4 is so low that it is already covered. At the same timethe tooth II, 6 is carried along, whereby the date 3. March is produced.The following changes of dates are normal as described under (1).

(d) Changes at the endofl a month with 30 days, for instance April:

A short tooth of the disc II corresponding to a month of 30 days andproducing the change, for instance the tooth II, 9, which is providedfor the changing over from April to May, is higher by one circle thanthe corresponding tooth of the same disc which is provided for a monthwith 31 days. tweenthe teeth III, 31 and III, 1 which corresponds to thenumber of the 31st day. While the pawl Z moves, the disc III rotates inthe normal way to the date 31, but tooth II, 9 is also moved, wherebythe inscription of the disc III in the opening P1 of the front plate iscovered by the inscription r1..May. The tooth II, 10 which, before this,covered the higher teeth of disc III, and spaced 5/31 from the edge k-Zof the disc III, has now been moved forward by j/25 of thecircum'ference, whereby the ,tooth III, 2 has been uncovered. In thefollowing change the pawl Z drives the tooth III, 2 bringing thereby thenumber 2 of the day within the opening P1, and the tooth II, 10 pushingbehind the opening of the plate O the other inscription May and one ofthe openings La, through which the number 2 can be read.

The now following changes of the date are normal as described under (1).

(3) Changes of the years (a) Normal year: On December 31st there are inposition on the -discs III and II the deepest notches, viz. the

notches between III, 1 and III,2 and between II, 25 and II, 1,respectively. In the changing over from December 31st to January -1stthe pawl Z drops down until it reaches the teeth of disc IV, whichcarries the unitsv of` the years, 'bringing about a rotation of thisdisc to the extent of one tooth to display the unit of the followingyear.

(b) Leap year:

For a leap year a tall tooth of the disc IV is adjusted to overtop theedge g-h. To the end that this tooth may be shifted behind the edgelc-Z, the change of the year must be carried through the two parts. Thepawl Z grasps, during the changing over to January 1st, of the yearfollowing a leap year, in the notches III, l-III, 2 and. II, 25-II, I' alow tooth of the disc IV which precedes a high tooth, and during thechanging over to January 2nd it catches this high tooth. For this reasonthe disc IV carries twice in succession the units of the years, whichfollow a leap year. Thereafter the normal state is established again.

I arrange the inscriptions on the discs in a well defined manner inorder that they appear exactly in the openings of the plate O.

In the calendar illustrated in the drawings the -straight line a, b, cis the longitudinal axis ofthe openings P1 and P3, which form a part ofthe opening of the front plate (see Figs. 1 and 8).

It therefore overtops already the notch be- The production of the edgek-l to the point b,

which need not necessarily be the centre of the disc O, includes withthe straight line a, b, c an angle r. Therefore every inscription on thediscs, which marks a day or month, is arranged in an axis which on thedisc, on which this inpendicular to lines which include with theproduced active edges oi.` the teeth, which must be engaged to displaythe single units, the angle 1'; the same is true of the transverse axisof `the inscriptions Forenoon and Afternoon on disc V, where the angle sis a right angular one.

The calendar may easily be combined with :a clock, for instance as shownin Figs. 1, 2 and 3. The front plate is formed as agdial, and thespindles carrying the hands traverse the hollow journal U. Theclock-work Q of some usual kind, may be fixed with its casing to theback of the calendar and may be provided with means for actuating thecalendar twice a day, preferably at midnight and noon. Such means maycomprise a pin R attached to the back of the calendar or of theclock-work or its casing. On this pin is mounted for free pivotalmovement the flat lever Y which car'ries on its one end the resilientpawl Z. Spring means R1 are arranged to press the lever Y with the pawlZ towards the edge lc-l. By the pin S the lever Y abuts against thespiral cam member X which is rigidlly mounted on the shaft of the shorthand of the clock and thus performs one complete rotation Within twelvehours.v During this rotation the member X lifts the lever Y towards thepoint f; at twelve oclock the outer end of the cam comes to lie againstand to slip o, the stop S, whereafter the lever Y, pressed by the springR1, moves with the pawl Z towards the edge k-L the full date or theforenoonafternoon-indication being now changed. In order to prevent thelever Y from moving too rapidly, I provide an edge v along which thestop S, after being freed from the cam, is forced to slide; the edge vlies between the two ends of the spiral cam member X and differsslightly in form from the circle. m, the centre of which is the pin R,as may be seen in Fig. 3.

Should the clock stop,` for instance when not wound up, the date may bemanually adjusted by shifting the discs in the openings by the aid of aneedle or the like. After the date has been so adjusted and the clockwound up, the calendar again operates in a perfectly automatic andreliable manner.

As mentioned above, the calendar will operate infinitely without anycorrection being required except in a century, the number of which isnot divisible by 400. If this correction shall also be avoided, the formof the teeth must be altered gorrespondingly.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.l

I claim:-

l. An automatic calendar for manual or mechanical adjustment of thedates comprising in combination, a front plate with an opening therein,a back, discs concentrically mounted be- .hind and substantiallyparallel to said front plate for free rotation about a common axis, anintermediate ring plate secured against rotation between two of saiddiscs, said intermediate ring plate having a recess with a profilededge, while said discs have openings formed therein and inscriptions forthe display of a date, behind said opening of the front plate, profiledteeth of diiferent heights on the circumference of said discs forovertopping in turn the profiled edge of the recess of said ring plate,notches of different depths being formed in the discs between saidteeth, theL teeth of one disc being partly overlapped by and partly.overlapping those of another disc, and means for periodically rotatingone or more ofV said discs comprising a pawl adapted to slide in `saidrecess and being resiliently pressed towards the profiled edge of saidrecess to carry along those teeth, an edge-0f which is inposition to beengaged by it.

2, Automatic calendar for manual or mechanical adjustment of the dates,comprising in com- ,bination, a front .plate with an opening therein,V

a back, discs concentrically mounted behind and substantially parallelto said front plate for free rotation .about a common axis, anintermediate ring plate secured against rotationbetween two of saiddiscs, said intermediate ring plate havlng a recess with a profilededge, while said discs have openings and inscriptions for the display ofa date, behind the opening of the front plate, pronled teeth ofdifferent heights on the circumference of said discs for overtopping inturn the profiled edge of the recess of said ring plate, said discshaving notches of different depths between said teeth, the teeth of onedisc being partly overlapped by and partly overlapping those of anotherdisc, and means for periodically rotating one or more of said discsevery twelve hours comprising a clock-work and a pawl adapted to slidein said recess and being resiliently pressed towards the proled edge ofsame to carry along those teeth, an edge of which is in position to beengaged by it.

3. Automatic calendar for manual or mechanical adjustment of the dates,hours and times of day comprising in combination, a clock, a front platewith an opening therein forming also the dial of said clock, a bachwhich has formed therein an opening, a hollow journal between said frontplate and said back, a shaft arranged in said hollow journal to carry 'ahand of said clock, discs concentrically mounted behind andsubstantially parallel to said front plate for free rotation about saidhollow journal, an intermediate ring plate secured against rotationabout said journal between two of said discs, said intermediate ringplate having a recess with a prolled edge, while said discs haveopenings formed therein and inscriptions for the display of a date,behind the opening of the front plate and to the rear of the opening ofsaid back; proled teeth of different heights on the circumstance of saiddiscs for overtopping in turn the proled edge of the recess of said ringplate, notches of different depths being formed in said discs betweensaid teeth, the teeth of one disc being partly overlapped by and partlyoverlapping those of another disc, and means controlled by said clocki'or periodically rotating `said discs comprising a pawl adapted vtoslide in said recess and being resiliently pressed towards the profilededge thereof to carry along all 'thosev teeth, an edge of which is inposition for engagement.

4. Automatic calendar for manual or mechan-` ical adjustment of thedates in accordance with the present prevailing calendar-systemcomprising in combination, a front plate with an opening therein, a backwhich has an opening formed vso therein, ive discs concentricallymounted behind and substantially parallel to said front plate for freerotation about a common axis, an intermediate ring plate secured againstrotation between two of said discs, said intermediate ring plate havinga recess with a proled edge, while said discs have openings andinscriptions, for the display of a date, behind the opening of the frontplate and to the rear of the opening of the back, proiiled teeth ofdiierent heights formed on the outer edge of said discs for overtoppingin turn the proiiled edge of the recess of the back, the number of teethon each disc being equal to that of the inscriptions arranged on thisdisc, notches of different depths being formed in said discs betweensaid teeth, the heights of said teeth and the depths of said notchesbeing defined by points of intersection of nine concentric circles, thecentres of which lie on said common axis, with radial rays which definethe active edges of said teeth, the teeth of one disc being partlyoverlapped by and partly overlapping those of another disc, and meansfor periodically rotating said discs comprising a pawl adapted to slidein said recess and beingy resiliently pressed towards the proled edge ofthe same to carry along all those teeth, an edge of which is in positionfor engagement. l

. 5. 'I'he automatic calendar of claim'4, in which the irst disc bearsseven inscriptions, one for each day of the week, seven teeth beingformed on its circumference and openings formed in said disc between theinscriptions adapted to display in the opening of the front plate theinscriptions arranged on some other disc.

6. The automatic calendar of claim 4, in which the second disc carries25 inscriptions, two in succession for each month of the year other thanMarch and three in succession for the month of March, 25 teeth beingformed on its circumference and marks indicating the first day of everymonth arranged next to every rst of said marks for each-,of the months,said disc having openings formed therein one arranged next to everysecond mark for each of the months other than March and one next to thethird mark for the month of March, these openings being arranged todisplay in the opening of the front plate the inscriptions carried bythe third disc, and openings formed in said second disc, one arrangednext to each of said 25 inscriptions vadapted to 'display in the openingof the front plate the inscriptions carried by the fourth disc.

'7. The automatic calendar of claim 4, in which the third*r disc carries31 figures for the days of the'month, and is formed with openingsadapted to display in the opening o f the front plate the inscriptionscarried by the fourth plate, 31 teeth being formed on thecircumferenceof said third disc.

8. The automatic calendar of claim 4, in which the fourth disc carries25 figures, viz. twice in succession the series of gures from zero tonine, wherein the figures 3 and 7 in the one succession, and the iigures1, 5 and 9 in the other one are repeated, and 25 teeth on thecircumference of said fourth disc.

,9. The automatic calendar of claim 4, in which the fth disc is formedwith eight teeth on its circumference and carries on its back four marksfor forenoon in alternation with four marks for afternoon, each of thesemarks being adapted to register with the opening in said back so as tobe visible therethrough.

10. The automatic calendar of claim 4, in which eight teeth are formedon the circumference of the fth disc, the notches between these teethextending alternately `down at least to the innermost of the ninecircles and only to the outermost one, the said iifth disc having fourmarks on the back for forenoon in alternation with four marks vforafternoon, each one of these marks being adapted to register with theopening in said back so as to be visible therethrough.

11. The automatic calendar of claim 4, in which the circles are letteredfor reference from A to J, omitting the letter I, beginning with theoutermost circle in/ which the intermediate ring plate is formed with anouter recess, one edge of which is formed by part of a radius of saidcircles, while its inner delimitation extends from the point ofintersection of the radius andthe innermost of said circles, followingthis circle for 1/25 of its circumference extending from here right to apoint on the circle lettered D spaced from said radius 3&1 of thecircumference of the circle, from this point to a point on the outermostbut one of said circles spaced from said radius 9&5 of the circumferenceof the circle thereafter following this latter circle until it reaches apoint spaced from said radius 1/1 of the circumference ofthe circle andthen extendingv tothe outermost circle, meeting thesame at a pointspaced from said radius a little more than V7 of its circumference.

12. The automatic calendar oi' claim 3, in which the means forperiodically rotating the discs comprise, apart from the pawl, a pincarried by the back and arranged outside the center of said back, alever mounted for free rotation about said pin and carrying said pawl,spring means for pressing said lever with said pawl towards a radialside edge of the recess in the intermediate ring plate, a pin carried bysaid lever and a spiral member against which abuts said pin and which isarranged to rotate in conformity with the shaft of the short hand ofsaid clock and to force said lever against the action of said springmeans with said pin away from said centre, releasing it every twelfthhour for guiding said pawl at once through said recess towards theradial edge of the same.

13. The automatic calendar of claim 3, in which the means forperiodically rotating the discs comprise, apart from the pawl, aclockwork carried by thekback, a pin carried by the back and arrangedoutside of the centre of lsaid back, a lever mounted for free rotationabout said pin and carrying said pawl, spring means for forcing saidlever with said pawl towards a radial side edge of the recess in theintermediate ring plate, a stop associated with said lever and a memberhaving a spiral edge, against which abuts said stop', said member beingarranged to rotate in conformity with the shaft of the short hand ofsaid clock and to force said lever with said stop against the action ofsaid spring means away from said centre, releasing it every twelfth hourfor guiding said pawl at once through said recess towards the radialedge of the same, and said member having a curved edge connecting thetwo ends of said spiral edge for guiding said stop, whenvreleased bysaid member, with reduced speed.

ZDENK JIsKaA.

